The present application is directed to methods and devices for controlling operation of an image forming device and, more specifically, to methods and devices for detecting the presence of machine modules installed in the image forming device as well as the presence of a media sheet as it moves along a media path within the image forming device.
The image forming device moves a media sheet through an extended media path, beginning at an input area where the media sheet is picked from a removable media input tray or inserted through a manual feed. The media sheet undergoes numerous operations along the media path such as image transfer onto the media sheet, and adhering the image to the media sheet.
Several sensing functions may be desired for controlling operation of the image forming device, such as detecting the leading edge position of the media sheet and presence of the media sheet in the media path. In addition, operation of the image forming device may depend on proper installation of various removable machine modules. For example, the image forming device may not operate if the media input tray is not installed or is not installed properly or if a cover is open.
Using a separate sensor for each of these sensing functions may increase the cost and complexity of the image forming device. In addition, more complex sensors that produce a variable signal in response to a sensed signal may require frequent calibration which may affect reliability and increase maintenance requirements. Image forming devices, however, should be constructed in an economical manner without adversely impacting reliability. Both cost reduction and improved system reliability may be obtained by integrating the functions of a plurality of sensors into fewer components.